Published: January 13, 2010

PORT-AU-PRINCE, Haiti — Survivors strained desperately on Wednesday against the chunks of concrete that buried this city along with thousands of its residents, rich and poor, from shantytowns to the presidential palace, in the devastating earthquake that struck late Tuesday afternoon.

The New York Times

Calling the death toll “unimaginable” as he surveyed the wreckage, Haiti’s president, René Préval, said he had no idea where he would sleep. Schools, hospitals and a prison collapsed. Sixteen United Nationspeacekeepers were killed and at least 140 United Nations workers were missing, including the chief of its mission, Hédi Annabi. The city’s archbishop, Msgr. Joseph Serge Miot, was feared dead.

And the poor who define this nation squatted in the streets, some hurt and bloody, many more without food and water, close to piles of covered corpses and rubble. Limbs protruded from disintegrated concrete, muffled cries emanated from deep inside the wrecks of buildings — many of them poorly constructed in the first place — as Haiti struggled to grasp the unknown toll from its worst earthquake in more than 200 years.

In the midst of the chaos, no one was able to offer an estimate of the number of people who had been killed or injured, though there was widespread concern that there were likely to be thousands of casualties.

“Please save my baby!” Jeudy Francia, a woman in her 20s, shrieked outside the St.-Esprit Hospital in the city. Her child, a girl about 4 years old, writhed in pain in the hospital’s chaotic courtyard, near where a handful of corpses lay under white blankets. “There is no one, nothing, no medicines, no explanations for why my daughter is going to die.”

Governments and aid agencies from Beijing to Grand Rapids began marshaling supplies and staffs to send here, though the obstacles proved frustrating just one day after the powerful 7.0-magnitude earthquake hit. Power and phone service were out. Flights were severely limited at Port-au-Prince’s main airport, telecommunications were barely functioning, operations at the port were shut down and most of the medical facilities had been severely damaged, if not leveled.

A Red Cross field team of officials from several nations had to spend Wednesday night in Santo Domingo in the Dominican Republic to gather its staff before taking the six-hour drive in the morning across the border to the earthquake zone.

“We were on the plane here with a couple of different agencies, and they all are having similar challenges of access,” Colin Chaperon, a field director for the American Red Cross, said in a telephone interview. “There is a wealth of resources out there, and everybody has the good will to go in and support the Haitian Red Cross.”

The quake struck just before 5 p.m. on Tuesday about 10 miles southwest of Port-au-Prince, Haiti’s capital, ravaging the infrastructure of Haiti’s fragile government and destroying some of its most important cultural symbols.

“Parliament has collapsed,” Mr. Préval told The Miami Herald. “The tax office has collapsed. Schools have collapsed. Hospitals have collapsed. There are a lot of schools that have a lot of dead people in them.”

He added: “All of the hospitals are packed with people. It is a catastrophe.”

Mr. Obama said that United States aid agencies were moving swiftly to get help to Haiti and that search-and-rescue teams were en route. He described the reports of destruction as “truly heart-wrenching,” made more cruel given Haiti’s long-troubled circumstances. Mr. Obama did not make a specific aid pledge, and administration officials said they were still trying to figure out what the nation needed. But he urged Americans to go to the White House’s Web site, www.whitehouse.gov, to find ways to donate money.

“This is a time when we are reminded of the common humanity that we all share,” Mr. Obama said, speaking in the morning in the White House diplomatic reception room with Vice President Joseph R. Biden Jr. at his side.

Aid agencies said they would open their storehouses of food and water in Haiti, and the World Food Program was flying in nearly 100 tons of ready-to-eat meals and high-energy biscuits from El Salvador. The United Nations said it was freeing up $10 million in emergency relief money, the European Union pledged $4.4 million and groups like Doctors Without Borders were setting up clinics in tents and open-air triage centers to treat the injured.

Supplies began filtering in from the Dominican Republic as charter flights were restarted between Santo Domingo and Port-au-Prince.

Some aid groups with offices in Port-au-Prince were also busy searching for their own dead and missing.

Sixteen members of the United Nations peacekeeping force in Haiti were killed and as many as 100 other United Nations employees were missing after the collapse of the mission’s headquarters in the Christopher Hotel in the hills above Port-au-Prince.

Forty or more other United Nations employees were missing at a sprawling compound occupied by United Nations agencies. Ten additional employees had been in a villa nearby.

It was one of the deadliest single days for United Nations employees. The head of the group’s Haitian mission, Mr. Annabi, a Tunisian, and his deputy were among the missing, said Alain Le Roy, the United Nations peacekeeping chief.

Earlier Wednesday, the French foreign minister, Bernard Kouchner, said in radio interviews that Mr. Annabi had been killed in the collapse.

The Brazilian Army, which has one of the largest peacekeeping presences in Haiti, said 11 of its soldiers had been killed in the quake and seven had been injured; seven more were unaccounted for.

During a driving tour of the capital on Wednesday, Bernice Robertson, an analyst with the International Crisis Group, said she saw at least 30 bodies, most covered with plastic bags or sheets. She also witnessed heroic recovery efforts. “There are people digging with their hands, searching for people in the rubble,” she said in a video interview via Skype. “There was unimaginable destruction.”

When staff members tried to travel by car, “they were mobbed by crowds of people,” Mr. McPhun said. “They just want help, and anybody with a car is better off than they are.”

Contaminated drinking water is a longstanding and severe problem in Haiti, causing high rates of illness that put many people in the hospital. Providing sanitation and clean water is one of the top priorities for aid organizations.

More than 30 significant aftershocks of a 4.5 magnitude or higher rattled Haiti through Tuesday night and into early Wednesday, according to Amy Vaughan, a geophysicist with the United States Geological Survey. “We’ve seen a lot of shaking still happening,” she said.

Bob Poff, a Salvation Army official, described in a written account posted on the Salvation Army’s Web site how he had loaded injured victims — “older, scared, bleeding and terrified” — into the back of his truck and set off in search of help. In two hours, he managed to travel less than a mile, he said.

The account described how Mr. Poff and hundreds of neighbors spent Tuesday night outside in a playground. Every tremor sent ripples of fear through the survivors, providing “another reminder that we are not yet finished with this calamity,” he wrote.

He continued, “And when it comes, all of the people cry out and the children are terrified.”

Louise Ivers, the clinical director of the aid group Partners in Health, said in an e-mail message to her colleagues: “Port-au-Prince is devastated, lot of deaths. S O S. S O S ... Temporary field hospital by us at UNDP needs supplies, pain meds, bandages. Please help us.”

Photos from Haiti on Wednesday showed a hillside scraped nearly bare of its houses, which had tumbled into the ravine below.

Simon Romero reported from Port-au-Prince and Santo Domingo, Dominican Republic. Reporting was contributed by Marc Lacey and Elisabeth Malkin from Mexico City, Ginger Thompson and Brian Knowlton from Washington, Neil MacFarquhar, Denise Grady and Liz Robbins from New York, and Mery Galanternick from Rio de Janeiro.

A version of this article appeared in print on January 14, 2010, on page A1 of the New York edition.